A cholic acid-based fluorescent chemosenor for the detection of ATP

A novel ditopic cholic acid-based fluorescent chemosensor for ATP, 1a, was designed and synthesized. Its interactions with phosphates, AMP, ADP, ATP, CTP, GTP, and TTP have been investigated. When ATP was added to a 1: 1 aqueous CH₃CN solution of the sensor at pH 7.4, a significant decrease in fluorescence of 1a was observed, whereas other guest molecules showed a much smaller effect. The complex between 1a and ATP was confirmed through combined UV, ¹H, ¹³C and ³¹P NMR spectroscopic methods. The uniqueness of the new sensor is that it binds with ATP 33-124 times more selectively than other nucleotides, as evidenced from the respective binding constants. 1a is a highly sensitive sensing probe; as little as 30 nM ATP can cause 15% fluorescence quenching of the sensor.